Two guest stars are set to hit the stage for
Psych's long-awaited musical episode.

Brooke Lyons ("2 Broke Girls") will play "Elisa," a playwright's muse and an original member of the cast of an ill-fated musical. (Which our psychic powers are telling us is called "Ripper!" -- but the network has not confirmed.)

Anthony Rapp, who starred in "Rent" on Broadway and the film version, has been cast as "Z," the playwright.

As
we learned at Comic-Con this summer, the "Psych" musical is taping in October, using original songs written by creator
Steve Franks (who also wrote and performs the "Psych" theme song). Considering the incredible vocal talents of stars
James Roday and
Dulé Hill, the musical promises to be at least as awesome as a koala bear and a jetpack. Don't believe us? Watch their covers of "Don't You (Forget About Me)" and "Ebony and Ivory" below. You're welcome.

USA is expected to announce the Season 7 premiere date for "Psych" soon.